Ignition Noise Effects on Land Mobile Communications Receivers

Automobile ignition noise effects on land mobile communications receivers are a function of engine rpm, the antenna position relative to the vehicle, and the type of spark plugs and wires used in the ignition system. Techniques for the suppression of these effects involve the use of proper shielding and pulse type electronic noise suppression circuitry built into the receiver. There are limitations to the effectiveness of electronic noise suppression. These limitations result from both high repetition rate bursts of ignition noise and interference effects caused by off-channel carriers.